This invention relates to a planetary gear consisting of a sun gear, a non-rotating internal spur gear or hollow gear and at least two planet gears meshing with the teeth of the sun gear and the spur gear, the planet gears being connected by a planet link.
Because of their compact construction and large reduction gear ratios, planetary gears are frequently used for the drives of automotive vehicles and other mobile power plants. Planetary gears may also be used for robust stationary drives, for example, for driving rolling mills and the like.
The play normally present in planetary gears is generally of no account. This is because the high quality of modern gear cutting machines permits this distance to be maintained within narrow limits.
The freedom of play of a drive, however, is of particular importance for adjustment drives having a changing direction of rotation when, for example, the turnstile of a directional antenna or of a telescope is driven. In this case even a small deviation from a predetermined position of a drive can cause considerable impairment of the performance. Therefore, planetary drives of the prior art were not favored for use in exact adjustment drives.